1687cb4 Refactor: One CBaseChainParams should be enough (Jorge Timón)
Pull request description:
There's no need for class hierarchy with CBaseChainParams, it is just a struct with 2 fields. This starts as a +10-43 diff
Tree-SHA512: 0a7dd64ab785416550b541787c6083540e4962d76b6cffa806bb3593aec2daf1752dfe65ac5cd51b34ad5c31dd8292c422b483fdd2d37d0b7e68725498ed4c2d
Backport of Core PR12128
https://github.com/bitcoin/bitcoin/pull/12128/